Closure for flexible packages



Aug.19,1969 y, '-A;PCQRLLA 3,462,070

CLOSURE FOR FLEXIBLE PACKAGES Filed Feb. 5, 196s United States Patent O 3,462,070 CLOSURE FOR FLEXIBLE PACKAGES Arthur P. Corella, 8166 Vanscoy Ave., North Hollywood, Calif. 91605 Filed Feb. 5, 1968, Ser. No. 703,013 Int. Cl. B65d 31/12, 33/16 U.S. Cl. 229-56 10 Claims ABSTRACT F vTHE DISCLOSURE BACKGROUND OF THE INVENTION The present invention relates generally to packages and containers made from thin, flexible sheet materials, and lmore especially to closure means for such packages which can -be formed under heat and pressure when the sheet material is heat sealable on one or -both faces. A particular advantage of the invention is in the construction which permits its use to divide the interior of a package into two separate compartments in such a manner that the compartments can be placed in communicatons with each other without opening the package; but the invention is not limited thereto in all of its aspects.

Various designs of packages are known in which means are provided to divide the interior of the package into two or more separable compartments. Such packages are designed to hold different substances, one substance in each compartment, isolated from each other in such a way that the substances can be stored Without any intermingling of them until desired. The substances in the packages may be in the form of a dry material in powder or tablet form, or a liquid, in either both compartments. v.A typical package is one having two compartments and a dry material in one compartment is to be mixed with a liquid contained in the other compartment. By removing the barrier between the two compartments while maintaining the exterior walls of the package intact, the two substances in the two different compartments can be mixed ,together in the interior space of the container and then discharged from the package asa mixture, after making a suitable opening in the outer walls of the package.

A container of this general character requires that the outerwalls be flexible and strong so that the Walls can be deformed, if necessary, to move the contents from one compartment to the other and back again as may be required to effect mixing of the ingredients. Also, in some designs of containers, internal barrier means are provided which must be ruptured byl pulling on the Walls of the package.

Various designs of barrierl constructions for multiple compartment packages have been evolved using an added member or sealing means, yeither inside or outside the package. Such designs have added to the complexity, and, accordingly, added to thecost of the package.

In an effort to` overcome this, it has been proposed to provide means separating the compartments by sealing the outer walls ofthe package together face-to-face by a simple bar seal. However, heretofore, `seals of this character have been unsatisfactory because by previously known techniques it has not been possible to make a seal which is of adequate and reproducible strength. The

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various factors affecting the strength of the seal have been so hard to control that the seals have generally been either too strong, and therefore not easily opened, or too Weak, and therefore break prematurely. From a practical standpoint, any seal or other barrier between the container compartments, or a closure for a single compartment, is highly unsatisfactory when it is not reproducible within narrow limits of strength but instead exhibits a wide variation in breaking strength. Y l.

Accordingly, it is a general object of the present invention to provide a closure for one compartment, or be'- tween two compartments, which is simple and economical in design and eliminates the addition tothe package of any extraneous members or closure elements, either to open or close the package.

It is also an object of the present invention to provide in a package of flexible film a seal or closure of simple construction which is capable lof reproduction in breaking strength within narrow limits thereby insuring a uniform product at all times.

It is a further object of the invention to provide aclosure means particularly adapted to lilms or sheet materials which are heat sealable on either one side or two sides, thereby adapting the construction to maximum range of materials available for packages.

SUMMARY OF THE INVENTION The advantages and objects of the present invention are achieved in a package of thin, flexible sheet material comprising a pair of overlying outer walls that are heat sealable on their inner faces, or on both inner and outer faces, and are joined together to form between the walls at least one product-holding space open at one side thereof. The package may be formed by a flattened tube or `by two separate sheets which are joined together vby heat seals along opposite margins thereof. In the completed package, at least one product is in the interiorspace.

The closure means may divide the product space into` two separate compartments, or it may close one side of a single product containing space. In either package, the closure means closes one side of a `product-holding space and comprises a plurality of folds in the outer walls extending transversely across the package bringing the inner surfaces ofl the walls into mutual contact at a plurality of thicknesses of material, and a light bond between said contacting inner surfaces formed by heat and pressure over an area between and spaced from the transverse folds. The inner bond closes the passage by which product can escape from the compartment. If the material is heat sealing on two sides, the louter surfaces in mutual contact are also lightly bonded together. The latter bond serves to hold the walls in folded position and to'in-` hibit separation of the walls and consequent rupture of the inner bond.

DESCRIPTION. oF THE DRAWING How the above and other objects and advantagesof the present invention are attained will be more readily understood by reference to the following description of the annexed drawings, in which:

FIG. 1 is a front and side perspective view of a filled single compartment package embodying the invention;

FIG. 2 is an enlarged fragmentary section on line 2-2 of FIG. 1; Y FIG. 3 is an enlarged fragmentary diagrammatic view l illustrating operations involved in applying the closure to two-compartment package embodying the present invention as a divider between the two compartments;

FIG. 6 is an enlarged fragmentary transverse section on line 6-6 of FIG. 5;

FIG. 6a is a fragmentary view similar to FIG. 6 of a variational embodiment;

FIG. 7 is a view similar to FIG. 5 showing the package therein as a container before filling;

FIG. 8 is a side View of the filled package showing the position it occupies when the two ends are pulled in opposite directions to straighten the folds and place the two compartments in communication with each other; and

FIG. 9 is a top and side perspective of a variational form of a multiple compartment package.

DESCRIPTION OF A PREFERRED EMBODIMENT The construction of the package or packages constituting the present invention will be most readily understood from a description of the method of making them; and, accordingly, there will follow a description of the sequence of operations resulting in the package illustrated in FIGS. 1 and 2. The operations required to manufacture the package, or similar ones, in a suitable sequence, may be performed manually or they may be performed upon production machinery, certain elements of which have been indicated diagrammatically in FIG. 3.

The package indicated generally at 10 in FIG. 1 is made from a length of seamless tubing which has been flattened to provide two overlying walls 11 and 12 integral with each other along opposite edges 10a of the package. The tubing is a length of thin film which is heat sealable on both inner and outer faces. As a preferred example of such material, the tube may be made of polyethylene film, but it will be understood that any other sheet materials, either homogeneous or laminated, that are heat sealable on one or both of their surfaces may be employed.

As an initial step, a piece of tubing is cut to the desired length. One end of the tube is then closed by flattening it and placing a transversely extending seal across the end of the tube, as indicated at 14, by the application of heat and pressure. Next, the package is filled through the remaining, still open, end. Any suitable product, either liquid or solid, can be placed in the product-holding space which is provided by the interior of the package between the two overlying walls 11 and 12. Alternatively, the closure next described may be formed to close one end of the tube, after which the package is filled. Finally, the remaining open side is closed by the face-to-face seal 14, thereby reversing the sequence of closing the two ends.

Next, the open remaining side of the product-holding space is closed by forming a plurality of folds in the walls of the tube which extend transversely across the tube and close the open end of the tube. One simple manner of forming these folds is illustrated in FIGS. 2 and 3. The end of the tube is placed between a pair of horizontally spaced pins 16 and 18 mounted on a connecting bar 19. By rotating the bar and pin 18 about the longitudinal axis of pin 16, an S-shaped configuration is produced at the end of the package, as shown in FIG. 3. Two approximately 180 folds are provided at spaced positions in the tube walls where they wrap around pins 16 and 18. Thus, three thicknesses of the tube, or a total of six wall thicknesses, are brought into overlying relationship.

Next, heat and pressure are applied to these overlying walls by a pair of heated sealing heads or platens 20 which bear against opposite sides of the multiple thicknesses of film. The application of heat and pressure in the manner indicated to the area 22 extending transversely across the flattened tube produces a light bond between the mutually contacting inner faces and outer faces of the tube.

It is well known that by the application of suicient heat and pressure, two films of polyethylene can be brought to, or substantially to, the melt point and bonded together by a heat seal, as at 14, which is substantially as strong as the films themselves. This type of seal is similar to an autogenous weld. However, according to the method of the present invention, the strength of the bond between two mutually contacting surfaces is limited to a value well below such a heat seal.

According to the present invention, heat and pressure are applied at values and in a manner to bring the multiple thicknesses of film between the platens 20 to a substantially uniform temperature which is close to, but below, the melt point of the film. It is desirable to approach closely to the melt point to soften the film, that is to within 10 F. or even 5 F. of the melt point; and a range of 5 F. to 10 F. below the melt point has been found to be highly satisfactory for the heads 20. The actual temperature depends on the melting point of the particular material used. A low density polyethylene will melt at l200 F. while a typical high density polyethylene may melt at as high as 250-260 F. Some preliminary testing may be required to establish the proper temperature for each film used; and it has been found that film supposedly of the same quality differs from one batch to another by a sufiicient amount to require testing of each batch.

Because of the multiple thicknesses of film, it is necessary to maintain pressure of the platens on the film for an appreciable length of time, typically approximately five seconds. The platens themselves are maintained at a temperature below the .melting point of the web in order not to overheat it; but by allowing the material to dwell between the platens for a sufficiently long period of time that the heat penetrates uniformly even to the inner layers of the wall material, all thicknesses of film approach the temperature of the platens and soften. The result is that all contacting surfaces of the web are lightly bonded together. As used herein, the term light lbond refers to a degree of adhesion between the two contacting surfaces of overlying films such that the films can be pulled apart without rupture or injury to the lm and yet are bonded together sufiiciently tightly to provide a hermetic closure which is a barrier to transmission of solid material or vapor across the bond.

From inspection of FIG. 2, it will be seen that the inner surfaces of the tube are bonded together in this fashion at three superimposed locations which are spaced apart along the length of the tube. Bonding together the inner faces of the tube in this manner insures the contents of the packages securely against loss of contents or moisture, and also against the entry of solids or gases from the exterior.

The contacting outer surfaces of the walls are also bonded together at two different locations, these latter bonds serving to keep the two 1801 bends in their original shape. At the same time, it is a relatively simple matter to open the package. This can be done by grasping the package at the end seal 14 and pulling the opposite end 24 in the opposite direction as indicated by arrow 25. Since the two walls `11 and 12 are not joined together at the extreme end 24 of the tube, the two walls may next be grasped individually and pulled apart to open the package for removal of its contents.

DESCRIPTION OF VARIATIONAL PACKAGES A variational form of single compartment package is illustrated in FIG. 4. This package is constructed in the same manner as the one previously described except that the package is formed from two separate webs which are brought into overlying relationship and are joined together by longitudinal marginal heat seals 31, which are ordinarily formed by the application of heat and pressure. This, in effect, provides a tube which is similar to the starting material for the package of FIG. 1. This tube is then closed at one end by placing the transversely extending seal 32 at that end. There is now formed a package having a product-holding space which is open at one side, through which a product is inserted into the package. Next the package is closed in the same manner 'as already described by applying heat and pressure to the area 34 extending transversely across the package. The heat and pressure are applied in a manner to provide a light bond between the mutually contacting inner surfaces and outer surfaces of the package. The plurality of folds extending transversely across the package may be formed in the same manner as illustrated in FIG. 3.

The application of the invention to a dual compartment package is illustrated by the package indicated generally at 40 in FIG. 5. This package may be, consideredas an extension of the package of FIG. 1 in which a longer tube provides a second product-holding compartment added at the other side of closure 22.

To produce the package 40, a length of seamless tubing has a plurality of transversely extending folds formed centralled of the package, instead of near one end. While the manner of forming these folds is not limitative upon the invention, they may be formed by the sequence of steps illustrated in FIG. 6. In the first operation, the package is first folded at 41 along a transverse axis located typically near the center of the package, that is approximately midway between the ends of the original length of tubing. Folding the package over on itself produces one fold at 41 which is a 180 jbend, as shown in broken lines.

Next the end of the package containing fold 41 is folded over on itself as indicated by arrow 42 in FIG. 6, forming a second fold 43 which is also a 180 bend but spaced from, although parallel to, fold 4`1 which has now reached the solid line position of FIG. 6.

These two folding operations result in four thicknesses of the tube, that is eight thicknesses of wall, being brought into` overlying relationship. These are then provided with a light bond between mutually contacting faces by applying heat and pressure, as indicated by arrows 45, to the area 46 between folds 41 and 43, said area extending transversely across the folded tube. There is a light bond over the area 46, as shown in FIG. 6. The complete interior of the original tube is now divided into two product-holding spaces, access to which is had through the opposite ends of the tube which remain open as shown in FIG. 7. Through these open ends, a suitable product can be introduced into each of the two compartments, after which the remaining open side of each compartment is closed by applying transversely extending heat seals as indicated at 48 in FIG. 5.

From FIG. 6, it will be apparent that the interior faces of the Walls of the tube are bonded together lightly at four superimposed locations spaced apart along the length of the original tube. The outer walls are now bonded together at three different locations, all now superimposed on each other. All these bonds overlie one another and are between the two folds 41 and 43 which are maintained in position by the bonds.

The method of forming these light bonds is the same as already described, that is, heat andpressure are applied to the overlying walls to bring :all of the plurality of thicknesses of walls between the sealing platens to a substantially uniform temperature which is close to but below the melting point of the film so that a bond is formed that is much weaker than the normal heat seal and is also unformly reproducible.

Just as the single compartment package may be made from two separate, overlying films which are bonded together longitudinally along opposite sides of the productholding compartment, so may the package of FIGS. 5-7 be made from two separate lms. In this instance, the package appears as in FIG. 9 in which the two films are bopded together over longitudinally extending marginal areas at opposite sides by heat seals 51, while the opposite ends of the two product compartments are 'closed by transversely extending heat seals 52. The area 46 extending transversely across the package is where the light bonds are applied. They are formed in the same manner as already described and serve to seal oif the two productcontaining compartments from each other.

An advantage of the packages illustrated in FIGS 5 and 9 is that the two compartments can be placed in communication with each other by removing folds 41 and 43 without breaking the exterior seals of the package. This permits the contentsof the two compartments to be intermixed within the package without any danger of leaking during the intermixing. If desired, the package can be opened later to discharge the mixed product. When it is desired to open the folds in order to effect intermixing of the products in the two compartments, this is done by spreading apart the end portions of the packages and then pulling the two ends in opposite directions as shown in FIG. 8. The forces applied to the bonds between the outer faces of the walls in the area 45 are in a direction to pull the walls apart and break the bonds on their exterior faces.

When the package has been straightened out, the light bondsbetween the interior faces of the walls can ,easily be broken by pressure applied to them by the contents of the package, by squeezing one compartment. This light bond is of very low strength and can be broken easily without breaking the walls of the package.

When the compartments are relatively full or large, the weight of the contents may tend to disturb the bond at the area 46 and straighten out seals 41 and 43. Any premature breaking of the bond can be resisted by lapplying a strip of adhesive tape as indicated at 55 in FIG. 9 to the outside surface of the package, the tape being applied in a manner to hold down fold 41 against the exterior surface of the package, thereby maintaining the two bends of at 41 and 43. Alternatively, a patch of adhesive, of a suitable kind, may be placed on the exterior surface to hold the fold 43, such adhesive being indicated at 56 in FIG. 6a.

From the foregoing description, it will be apparent that various changes in the` construction of the package and the method of producing it may occur to persons skilled in the art without departing from the spirit and scope of the present invention. Accordingly, it is to be understood that the foregoing description is considered as being illustrative of, rather than limitative upon, the invention disclosed herein.

I claim:

1. A package of thin flexible sheet material comprising:

a pair of overlying outer walls heat sealable on their inner faces and joined together to form a productholding space open at one side thereof;

a product in the space;

and means closing said open side, comprising a plurality of spaced folds in the outer walls extending transversely across the package bringing the inner surface of the walls at a plurality of thicknesses of material into mutual contact, and a light bond between said contacting inner surfaces formed by heat and pressure in an area between and spaced from the transverse folds, said bond holding the walls in folded position.

2. A package according to claim 1 in which the two walls are provided by a flattened tube, the walls being integrally joined along opposite edges of the package and sealed together across one end of the package.

3. A package according to claim 2 in which the bond area extends entirely across the package.

4. A package according to claim 1 in which the two walls are provided by separate sheets heat-sealed together around the product-holding space except at the open side thereof.

5. A package according to claim 1 in which the outer walls are heat sealable on both inner and outer faces and the opposing inner and outer surfaces in mutual contact are lightly bonded together over said area.

n 6. A package of thin flexible sheet material comprismg:

r7 i8 a pair of overlying outer walls heat scalable on their walls are provided by separate sheets heat-sealed together inner faces and joined together to form a product varound the product-holding space. holding space between the walls; 10. A package according to claim 6 in which the outer means dividing the product-holding space into two com- Walls are heat sealable on both inner and outer faces and partrnents each outside the other, said means corn- 5 the opposing inner and outer .surfaces in mutual contact prising a plurality of folds in the outer walls extendare lightly bonded together over said area. ing transversely across the package bringing the inner ysurfaces of the walls into mutual contact at a plurali- References Cited ty of thicknesses of material, and a light bond be- UNITED STATES PATENTS tween said contacting inner surfaces formed by heat 10 and pressure over an area between and spaced from 2584632 2/1952 Southwick the transverse folds, said bond closing the passage beutclfsont etlal zzgxs tween the two compartments. 3140039 7/1964 Ce 13e e a 22g- '62 7. A package according to claim -6 in which the two 3254829 6/1966 con 1 2 Walls are provided by a attened tube, the Walls being 15 3278109 10/1 66 009er 2 9"62 integrally joined along opposite edges of the package and 9 Salway 229-62 X sealed together across the ends of the package. DAVID M. BOCKENEK, Primary Examiner 8. A package according to claim 7 in which the bond area extends entirely across the package. US' C1' X'R' 9. A package according to claim 6 in which the twO 20 20G- 47; 22962, 66 

